Some form of display is used in just about every imaginable field of human endeavor. Any application in which information of some form or another is to be conveyed will most probably use one or more displays to convey that information. Displays, which include screens, monitors, such as computer and video monitors, and projectors are indispensable to engineering, scientific, educational, government, military and entertainment endeavors.
A common problem with displays is that an image will burn into the display after the image has been static or unchanging for a long period of time. Cathode ray tub (CRT), plasma, and liquid crystal display (LCD) displays are well known examples of displays that are susceptible to the burn-in problem. Of course, the longer a static image is displayed, the greater the probability that burn-in will result. Burn-in of the static image results in an objectionable pattern that becomes visible when the display changes to another image. For example, in cases where large numbers of video communications links are continuously monitored, it is common that one or more displays will brightly display the same, unchanging image, such as logos, test patterns, or color bars, for long periods of time. Burn-in of an image in expensive displays, such as costly video monitors and projectors, is of particular concern.